Update OpenCV test2

OpenCV_test/test2_colorconvert/main.cpp

@@ -1,10 +1,44 @@
 #include <opencv2/opencv.hpp>
 #include <iostream>
 #include <fstream>
+
 using namespace cv;
 
 int main(int argc, char ** argv){
     std::fstream infile;
-    Mat image;
-    
+    char filename[512];
+
+    // Read image filename from file
+    infile.open("filename.txt", std::ios_base::in);
+    if(infile.is_open()){
+        infile.read(filename, sizeof(filename));
+    }else{
+        std::cout << "No filename.txt" << std::endl;
+        return -1;
+    }
+
+    std::cout << filename << std::endl;
+
+    // Open the image
+    Mat image, image_hsv, image_gray;
+    image = imread(filename, IMREAD_COLOR);
+    if(image.empty()){
+        std::cout << "failed to open the image";
+        return -1;
+    }
+    cvtColor(image, image_hsv, COLOR_BGR2HSV);
+    cvtColor(image, image_gray, COLOR_BGR2GRAY);
+
+    // Show the converted images
+    namedWindow("Original Image", WINDOW_FREERATIO);
+    imshow("Original Image", image);
+    namedWindow("HSV Image", WINDOW_FREERATIO);
+    imshow("HSV Image", image_hsv);
+    namedWindow("Gray Image", WINDOW_FREERATIO);
+    imshow("Gray Image", image_gray);
+
+    waitKey(0);
+    destroyAllWindows();
+
+    return 0;
 }